Specifications

SiUS12-928_A Main Functions
Function and Control 34
1.6 Automatic Operation
Outline Automatic Cooling / Heating Function
When the AUTO mode is selected with the remote controller, the microcomputer automatically
determines the operation mode as cooling or heating according to the room temperature and the
set temperature at start-up, and automatically operates in that mode.
The unit automatically switches the operation mode to maintain the room temperature at the set
temperature.
Details Ts: Set temperature (set by remote controller)
Tt: target temperature (determined by microcomputer)
Tr: room thermistor temperature (detected by room temperature thermistor)
C: correction value
1. The set temperature (Ts) determines the target temperature (Tt).
(Ts = 18 ~ 30°C, 64 ~ 86°F).
2. The target temperature (Tt) is calculated as;
Tt = Ts + C
where C is the correction value.
C = 0°C (0°F): Cooling operation
C = 2°C (3.6°F): Heating operation
3. Thermostat ON/OFF point and mode switching point are as follows.
Tr means the room thermistor temperature.
N Heating → Cooling switching point:
Tr ≥ Tt + 2.5°C (4.5°F)
O Cooling → Heating switching point:
Tr < Tt – 2.5°C (4.5°F)
P Thermostat ON/OFF point is the same as the ON/OFF point of cooling or heating operation.
4. During initial operation
Tr ≥ Ts : Cooling operation
Tr < Ts : Heating operation
Ex: When the target temperature is 25°C (77°F)
Cooling → 23°C (73.4°F): Thermostat OFF → 22°C (72°F): Switch to heating
Heating → 26.5°C (79.7°F): Thermostat OFF → 27.5°C (81.5°F): Switch to cooling
(R11722)
Target temperature + 2.5˚C (4.5ºF)
Target temperature + 1.5˚C (2.7ºF)
= Thermostat OFF
Heating Operation
Target temperature – 2.5˚C (– 4.5ºF)
Cooling Operation
= Thermostat OFF
Target temperature – 2.0˚C (– 3.6ºF)